btrfs: reduce chunk_map lookups in btrfs_map_block()

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Currently we're calling btrfs_num_copies() before btrfs_get_chunk_map() in
btrfs_map_block(). But btrfs_num_copies() itself does a chunk map lookup
to be able to calculate the number of copies.

So split out the code getting the number of copies from btrfs_num_copies()
into a helper called btrfs_chunk_map_num_copies() and directly call it
from btrfs_map_block() and btrfs_num_copies().

This saves us one rbtree lookup per btrfs_map_block() invocation.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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Johannes Thumshirn 2024-08-13 13:36:40 +02:00 • committed by David Sterba

parent 6d752cacae

commit 0ae653fbec

1 changed files with 27 additions and 22 deletions

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fs/btrfs/volumes.c

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